Grapefruit juice is made from the meat of the fruit. Maybe that's the part one is to avoid. Just a guess.
Dude said any citrus may be used except for orange. So I'm guessing lemon and limes will do instead of grapefruit. It's the white stuff in the skin that has the Q.
I wonder if pomegranates could be used also.
I’ve considered pomegranate because of other health benefits.
I love orange juice, darn! But, I’m a big fan of lemonade also.